The value of property "UserPrincipalName" is used by another recipient object

Question

I'm stuck in some sort of strange loop.

I tried to create an office 365 user, and did not have any available licenses. I followed the link to purchase an additional license, then went back and created my new user.

You guessed it - I now had two, identical mailboxes.

I deleted the Office365 user, and used Powershell to remove the mailboxes.

I then attempted to recreate the user, but it failed again because the email address wasn't considered available.

Using Powershell: When I run get-mailbox, it does not show anything. When I run get-user, it shows name as "User" and name_ also as user.

Using the web interface, there is no user in Office365, but 3 identical users with the same email address in "Deleted Users". I have restored one of these, but there is no corresponding mailbox.

How can I purge everything so I am able to re-create the user, or at least be able to recreate the user?

When I go to the Office365 admin interface, there's a notice that I have an error:

Exchange: The value "<name@domain>" of property "UserPrincipalName" is used by 
another recipient object "namprd07.prod.outlook.com/Microsoft Exchange Hosted 
Organizations/<domain>.onmicrosoft.com/<user>_a999aaa999". Please specify a unique 
value.Exchange: An unknown error has occurred. 
Refer to correlation ID: d2effba4-de7d-45de-8984-02002fb04fe5

Answer 1

I had this.

The objects in the recycle bin on O365 still count as being valid, hence you get non-unique values. You can purge users from the O365 recycle bin using the following on your azure powershell prompt:

Remove-MsolUser –UserPrincipalName <account id> -RemoveFromRecycleBin

http://community.office365.com/en-us/forums/158/p/61879/233468.aspx#233468